---
title: Handle incoming request cancellation in Workers with Request.signal
description: Workers can now add event listeners on Request.signal and perform tasks when the request is cancelled by the client
image: https://developers.cloudflare.com/changelog-preview.png
---

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## Handle incoming request cancellation in Workers with Request.signal

May 22, 2025 

[ Workers ](https://developers.cloudflare.com/workers/) 

In Cloudflare Workers, you can now attach an event listener to [Request](https://developers.cloudflare.com/workers/runtime-apis/request/) objects, using the [signal property ↗](https://developer.mozilla.org/en-US/docs/Web/API/Request/signal). This allows you to perform tasks when the request to your Worker is canceled by the client. To use this feature, you must set the [enable\_request\_signal](https://developers.cloudflare.com/workers/configuration/compatibility-flags/#enable-requestsignal-for-incoming-requests) compatibility flag.

You can use a listener to perform cleanup tasks or write to logs before your Worker's invocation ends. For example, if you run the Worker below, and then abort the request from the client, a log will be written:

* [  JavaScript ](#tab-panel-1368)
* [  TypeScript ](#tab-panel-1369)

index.js

```

export default {

  async fetch(request, env, ctx) {

    // This sets up an event listener that will be called if the client disconnects from your

    // worker.

    request.signal.addEventListener("abort", () => {

      console.log("The request was aborted!");

    });


    const { readable, writable } = new IdentityTransformStream();

    sendPing(writable);

    return new Response(readable, {

      headers: { "Content-Type": "text/plain" },

    });

  },

};


async function sendPing(writable) {

  const writer = writable.getWriter();

  const enc = new TextEncoder();


  for (;;) {

    // Send 'ping' every second to keep the connection alive

    await writer.write(enc.encode("ping\r\n"));

    await scheduler.wait(1000);

  }

}


```

Explain Code

index.ts

```

export default {

  async fetch(request, env, ctx): Promise<Response> {

    // This sets up an event listener that will be called if the client disconnects from your

    // worker.

    request.signal.addEventListener('abort', () => {

      console.log('The request was aborted!');

    });


    const { readable, writable } = new IdentityTransformStream();

    sendPing(writable);

    return new Response(readable, { headers: { 'Content-Type': 'text/plain' } });

  },

} satisfies ExportedHandler<Env>;


async function sendPing(writable: WritableStream): Promise<void> {

  const writer = writable.getWriter();

  const enc = new TextEncoder();


  for (;;) {

    // Send 'ping' every second to keep the connection alive

    await writer.write(enc.encode('ping\r\n'));

    await scheduler.wait(1000);

  }

}


```

Explain Code

For more information see the [Request documentation](https://developers.cloudflare.com/workers/runtime-apis/request).